Treatment of hydrocarbon fractions



3 125 510 TREATMENT or HrnnocAnnoN FRACTIONS Kenneth Tupman and PeterThomas White, Snnhury-on- Thames, England, assignors to The BritishPetroleum Company Limited, London, England, a British joint-.

stock corporation No Draw'mg. Filed Oct. 24, 1961, Ser. No. 147,182Claims priority, application Great Britain Oct. 28, 1960 10 Claims. (Cl.208264) This invention relates to the treatment of hydrocarbonfractions, particularly petroleum fractions, boiling above 150 C., andthe principal object of the invention is to provide a process by meansof which the cloud point, pour point or freezing point of such fractionsmay be lowered.

According to the present invention a hydrocarbon fraction boiling above150 C. is contacted with a catalyst comprising a platinum group metal ona refractory oxide support in the presence of hydrogen and added halogenat a temperature of at least 600 F. and a pressure of at least 100'p.s.i.g., the temperature and space velocity used being correlated togive a product boiling above 150 C. having a pour point at least 5 F.lower than the pour point of the feedstock.

It has been found that the presence of added halogen gives a markedlygreater reduction in pour point compared with a similar operationwithout the halogen. In the case of the treatment of a heavy gas oilfeedstock having a pour point of 50 F. with a platinum-aluminahalogencatalyst for example, the presence of an added halogen compound gave areduction in pour point of 75 F. compared with a reduction of F. for asimilar operation without the halogen compound. The reduction of pourpoint of 75 F. was achieved with a yield of product (boiling above 150C.) of 80% wt.

The term fraction as used in this specification includes both fractionswhich are distillable at normal or reduced pressure, for example gasoils and waxy distillates, and also residues and portions thereof, forexample deasphalted residues. Particularly suitable fractions for use asfeedstocks are distillate fractions boiling within the range 150 to 450C. and more particularly within the range 250 to 450 C.

It has been found that it is not necessary to desulphurise the feedstockprior to submitting it to the pour point reduction process, althoughsuch a preliminary desulphurisation may be given if desired. Whenoperating with a sulphur-containing feedstock (-for example one withmore than 0.1% Wt. of sulphur) the process will normally effectconsiderable desulphurisation simultaneously with the lowering of thecloud point, pour point or freezing point. It has also been found thatthe process can be operated in the presence of considerable quantitiesof hydrogen sulphide, so that, for example, the process can be operatedon the total effluent of a previous hydrocatalytic desulphurisationprocess.

If desired, a part only of a particular distillate may be treated by theprocess according to the invention and the resulting product blendedwith the untreated portion of the distillate to give a final product ofreduced pour point.

The added halogen may be added to the reaction zone in any convenientmanner, for example by injecting it directly into the reaction zone, byadding it to the hydrogen-containing gas used, or, preferably, by addingit to the feedstock. Examples of suitable halogens are fluorine,

3,125,510 Patented Mar. 17, 1964 chlorine, and bromine, the former beingpreferred because corrosion difliculties are minimised. The halogen maybe added as such, or as a halogen compound which is decomposable tohalogen under the reaction conditions. Preferred halogen compounds arethose having halogen together with one or more of the elements carbon,hydrogen or oxygen, for example hydrogen halides and halogen derivativesof aliphatic hydrocarbons having from 1 to 4 carbon atoms. The halogenis preferably added in an amount from 0.001 to 1% wt. by weight offeedstock.

The platinum group metal content of the catalyst may be within the range0.01 to 5% wt., preferably 0.11.0% wt. The preferred platinum groupmetals are platinum and palladium. The refractory oxide support may beone or more of the oxides of metals of group II, III and IV of theperiodic table. Preferably it contains a major proportion of alumina andit may also contain a minor proportion of one or more of the otheroxides of metals of groups II, III and IV of the periodic table.Preferably the amount of the group II, III or IV metal oxides is from5-25% wt. of the support. Examples of suitable supports include alumina,silica/ alumina, titania/ alumina, zirconia/alumina and beryllia/alumina. The support material may also contain a minor proportion of oneor more compounds (including oxides) of non-metallic elements in groupsIII, IV and V for example boron or phosphorus, which may if desired becombined or mixed with any of the metal oxides of groups II, III and IV.Preferably the amount of the compounds of the non-metallic elements isfrom 5 to 25% Wt. of the support.

The catalyst may be halogen free or it may contain less than 1% wt. ofhalogen as disclosed in the complete specification of cognate UK. patentapplications Nos. 28,788/ 60, 37,123/ 60 and 5,774/61, or it may containat least 1% Wt. of halogen as disclosed in the complete specification ofUK. patent application No. 37,126/60, in addition to the halogen presentin the reaction zone by the addition of halogen. The catalyst may beemployed as a fixed bed, a moving bed, or in the fluidised state.

An essential requirement to obtain pour point reduction with any givencatalyst and operating conditions employed is a correlation oftemperature and space velocity. In general the higher the temperature,the higher the space velocity that can be employed, the upper limit oftemperature, at any given space velocity, being determined by the amountof cracking occurring. The feedstock used, the activity of the catalystused and the reduction of pour point required should also be taken intoaccount when selecting the process conditions. When treating the heavierfeedstocks, for example, the operating conditions may be more severe(i.e. conditions of higher temperature and/or lower space velocity) thanwhen treating lighter feedstocks.

When using a more active catalyst or when using a greater quantity ofadded halogen, less severe conditions may be used, an equivalentreduction in pour point being obtainable at a lower temperature and/orhigher space velocity.

Preferably the temperature is below that at which substantial crackingoccurs, and, for the purposes of the present specification substantialcracking is understood to occur when more than 20% wt. of the feedstockis converted to material boiling below C. Prefen ably not more than 15%wt. of the feedstock is so converted. In practice the temperature willnot normally exceed 950 F. and is preferably at least 700 F. Similarlyin practice the space velocity will not normally be less than 0.1v./v./hr. and more particularly not less than 0.5 v./v./hr. Preferablyit does not exceed 8 v./

used and inspection data on the feed and product were as follows:

Operating Conditions o ul 'cee v /hr and m re part1c arly it does not exd v /v Catalyst co Mo/alumma hr. The pressure may be from 100 to 1500p.s.1.g. and 5 Prewure p Sig 1000 the hydrogen:hydrocarbon mole ratiofrom 1:1 to 20:1. Temppratu'rg 730 The process may be operated with orwithout a net S pace velocity v./v./hr 2.0 hydrogen consumption. A nethydrogen consumption Gas recycle rate s.c.f./b 1000 is generallyfavoured by increase in pressure and for any given temperature and spacevelocity the pressure at R ul which the hydrogen consumption andhydrogen production are in balance is known as the equilibrium pres-Feed Product sure. It is generally preferred to operate at or above thispressure because this results in an increase in the onspecific Gravity 013/600 F M76 0850 stream time before catalyst regeneration orreplacement 15 i t is necessary. Another advantage of this type of oper-051j'g555ggg5555; jjjj 52 atlon is, for example, that when processingfeedstocks 3g? g gg g such as gas oils for the production of dieseloils, reducll fffi? f 1:: I: 395 tion of the diesel index is minimisedor avoided. The lg u ggg h 8g principal advantage of operating below theequilibrium 20 clogd f pjj""""' II: I: Q pressure is that a reduction inthe specific gravity of the Your Point, F 50 50 distillate is minimisedor avoided. P the FY0965S 115mg a d f 0f P y The hydrofined product wasthen processed over a is carried out in the normal manner, whicn 13 toincrease platinum Catalyst to reduce its pour point The Catalyst thetemperature gradually as the run continues in order composition tomaintain the quality of the product at the desired level. Percent wt Theprocess of the present invention will normally Platinum 0.75 lower allthe three points specified, viz. cloud point, pour Fluorine 0.35 pointand freezing point. Which point is taken as the 9 Chlorine 0.35criterion for any particular operation will depend on the Al ina Balancefeedstock used and the use to which the product is to be Four runs werecarried out In the first run them was P The freezlng P 1S normally onlyof lmponance no addition of a halogen compound to the reaction zone;

. g With the lower bolllng f 1n the second carbon tetrachloride wasadded to the feed- In c pendlng PP a 3/ 61 a procstock in an amount togive 0.1% wt. of chlorine by weight ess for the treatment of hydrocarbonfractions boiling of feedstock; in the third the amount of carbontetraabove 150 C. to reduce their cloud point, pour point, or chloridewas sufficient to give 0.5% wt. chlorine, and in freezing point isdescribed, in which the fractions are the fourth tertiary butyl chloridewas added in an amount first treated to reduce content of aromatichydrocarbons, g Wt. lorm or nitrogen compounds or both. go After theprocessing the product was stabilised to re- Such a process may ifdesired, be Combined with the move a small proportlon of material boningbelow 150 0 process of the present invention, as may the processes FEgave a gas 9f the requlred flash Pomt (1 50 disclosed in the copendingapplications referred to earlier, 5913 g used and results Obtained areviz. in the complete specification of cognate UK. appliglven a e e TABLE1 Pressure, p.s.i.g 500 500 500 500 Space Velocity, v./v./hr 1.0 1.0 1.01.0 Hydrogen Rate (once through), s.c.f./b. 5000 5000 5000 5000Feedstock DcsulphurisedHcavy Dcsulphurised Heavy Gas Desulphuriscd HeavyGas Desulphuriscd Heav Ga Gas Oil Oil containing 0.1% Wt. Oil containing0.5% wt. Oilcontaining0.5%wt.01 01 (added as carbon tctra- C1 (added ascarbon tetra- (added as tertiary butyl chloride) chloride) chloride)Operating Temperature,

F 775 800 825 775 800 825 775 800 825 775 800 825 Product(Unstabllised):

Cloud Point, F 54 50 44 42 26 12 28 16 12 24 s -4 Pour Point, F 50 40 3o20 10 25 15 -15 20 20 4.5

Feed Feed Feed Feed Product (Boiling 150 0.):

Cloud Point, F 60 66 60 60 26 12 -s Pour Point, F 50 50 20 -5 -25 Yield(based on feed),

Percent wt 100 92 100 100 100 90 cation Nos. 28,788/60, 37,123/60 and5,774/61 and in the complete specification of UK. application No.37,126/ 60.

The invention is illustrated by the following examples.

EXAMPLE 1 A heavy gas oil was hydrocatalytically desulphurised over acatalyst of 2.4% wt. cobalt oxide and 14.3% wt.

The results show the very much greater reduction in pour pointobtainable when operating in the presence of a halogen compound.

EXAMPLE 2 A comparison of the effects of fluorides, chlorides andbromides on the pour point reduction of desulphurised heavy gas oil wascarried out using the same catalyst,

molybdenum oxide on alumina. The process conditions 7 feedstock andfeedstock preparation as those used in Ex- O ample 1. Three runs Werecarried out, in the first tertiary butyl chloride was added to thefeedstock in an amount to give 0.1 percent weight chlorine by weight offeedstock; in the second tertiary butyl bromide was added to the 6 isconverted to material boiling below 150 C. and said selected spacevelocity being at least 0.01 v./v./hr. but not higher than 8.0 v./v./hr.at which, at said selected temperature, not more than 20% wt. of thefeedstock is feedstock to give 0.1 percent of bromine; in the thirdconverted to material boiling below 150 C.; maintaining tertiary butylfluoride was added to the feedstock to give a selected pressure in saidzone in the range 1001 500 0.1 percent weight fluorine. p.s.i.g.a., saidselected temperature and said selected space The process conditions usedand results obtained were velocity being correlated to reduce the pourpoint of the as follows: feedstock such that the pour point of thematerial of the Pressure, p.s.i.g 500 500 500 500 Space velocity,v./v./hr. 1.0 1.0 1.0 1.0

Hydrogen rate through), s.c.f./b Feedstock (once 5,000 DesulphurisedHeavy Gas Oil 5,000 Desulphurised Heavy Gas Oil containing 0.1 percentwt. 01 (added as 5,000 Desulphurised Heavy Gas Oil containing 0.1percent wt. F (added as tertiary 5,000 Desulphuriscd Heavy Gas Oilcontaining 0.1 percent wt. Br (added as tertiary butyl chloride)tertiary butyl bromide) butyl fluoride) Operating Temperature, F 775 8008 5 775 800 825 775 800 825 775 800 825 Feed Product Data:

Cloud Point, F 60 54 50 44 40 14 48 38 18 48 42 20 Pour Point, F 50 5045 40 15 5 30 5 45 40 5 EXAMPLE 3 treated distillate fraction boilingabove 150 C. is at least The same feedstock, feedstock preparation andcatalyst as that of Example 1 were used to study the effect of changesin process variables on the pour point reduction of desulphurised heavygas oil containing carbon tetrachloride in an amount to give 0.1 percentweight chlorine by weight of feedstock.

The process conditions used and results obtained were as follows:

Hours on Stream 10-12 34-36 84-86 100-102 116-118 140-142 OperatingConditions:

Feedstock Desulphurised Heavy Gas Oil Containing 0.1% wt. 01 CatalystPt/Alumina Reactor Pressure p 750 750 750 750 750 750 Reactortemperature, F 775 775 825 825 675 7 5 Space velocity, v./v./hr, 1.0 2.5 1. 0 2. 5 1.0 2. 5 Gas recycle rate, s.c.f./b 10,000 10,000 10, 00010, 000 10, 000 10,000

Feed

Product (150 0.):

Yield, percent wt 90. 2 94. 9 86. 6 93. 0 97. 7 97.6 Cloud Point, F 6028 46 6 36 58 60 Four Point, F 20 40 15 30 50 50 This exampleillustrates the necessity of correlating the temperature and spacevelocity to give a reduction in pour point. At 675 F. and 1 v./v./hr.,and 725 and 2.5 v./v./hr., the temperature is too low, at the spacevelocity used, to give pour point reduction. However, if the temperatureis raised to 775, pour point reduction is obtained at both spacevelocities, being greater at the lower space velocity. Raising thetemperature to 825 F. further reduces the pour point.

We claim:

1. A process for the treatment of distillate petroleum fractions boilingwithin the range 150450 C. to lower the pour point at least 5 F. withoutmaterial reduction in the specific gravity and diesel index of saiddistillate fractions, comprising contacting the distillate fraction asfeedstock in a treating zone and in the presence of hydrogen and ofhalogen added to the treating zone in an amount from about 0.001 to 1%by weight of feedstock with a catalyst comprising a platinum group metalon a refractory oxide support, the hydrogen to hydrocarbon mole ratiobeing from 1 to 1 to 20 to 1; maintaining a selected temperature and aselected space velocity in said zone, said selected temperature in saidzone being maintained at least at 700 F. but not higher than about 950F. and being a temperature at which, at said selected space velocity,not more than 20% wt. of the feedstock 5. A process as claimed in claim1 wherein the halogen is added in the form of a compound of halogen inwhich halogen is combined with at least one of the elements carbon,hydrogen and oxygen.

6. A process as claimed in claim 1 wherein the catalyst contains from0.01 to 5.0% wt. of the platinum group metal.

7. A process as claimed in claim 1 wherein the platinum group metal isplatinum.

8. A process as claimed in claim 1 wherein the space velocity is atleast 0.5 v./v./ hr.

9. A process as claimed in claim 1 wherein the space velocity does notexceed 5 v./v./hr.

10. A process as claimed in claim 1 wherein the pressure is from to 1500p.s.i.g., and the hydrogenzhydrocarbon mole ratio is from 1:1 to 20:1.

References Cited in the file of this patent UNITED STATES PATENTS2,793,984 Northcutt et al. May 28, 1957 2,885,352 Ciapetta et al. May 5,1959 2,888,397 Burton et a1. May 26, 1959 2,890,167 Haensel June 9, 19592,965,564 Kirshenbaum et al Dec. 20, 1960 3,085,971 Mooi et a1 Apr. 16,1963 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 3125 510 March I7 1964 Kenneth Tupman et al., It is hereby certified thaterror appears in the above numbered patent req'liring correction andthat the said Letters Patent should read as corrected below.

Column 3 line 35, for "No, 8238/61" read No, 8248/61 Signed and sealedthis 8th day of September 1964.,

SEA L) Attest:

ERNEST W. SWIDER Attesting Officer EDWARD J. BRENNER Commissioner ofPatents

1. A PROCESS FOR THE TREATMENT OF DISTILLATE PETROLEUM FRACTIONS BOILINGWITHIN THE RANGE 150-450*C. TO LOWER THE POUR POINT AT LEAST 5*F.WITHOUT MATERIAL REDUCTION IN THE SPECIFIC GRAVITY AND DIESEL INDEX OFSAID DISTILLATE FRACTIONS, COMPRISING CONTACTING THE DISTILLATE FRACTIONAS FEEDSTOCK IN A TREATING ZONE AND IN THE PRESENCE OF HYDROGEN AND OFHALOGEN ADDED TO THE TREATING ZONE IN AN AMOUNT FROM ABOUT 0.001 TO 1%BY WEIGHT OF FEEDSTOCK WITH A CATALYST COMPRISING A PLATINUM GROUP METALON A REFRACTORY OXIDE SUPPORT, THE HYDROGEN TO HYDROCARBON MOLE RATIOBEING FROM 1 TO 1 TO 20 TO 1; MAINTAINING A SELECTED TEMPERATURE AND ASELECTED SPACE VELOCITY IN SAID ZONE, SAID SELECTED TEMPERATURE IN SAIDZONE BEING MAINTAINED AT LEAST AT 700*F. BUT NOT HIGHER THAN ABOUT950*F. AND BEING A TEMPERATURE AT WHICH, AT SAID SELECTED SPACEVELOCITY, NOT MORE THAN 20% WT. OF THE FEEDSTOCK IS CONVERTED TOMATERIAL BOILING BELOW 150*C. AND SAID SELECTED SPACE VELOCITY BEING ATLEAST 0.01 V./V./HR. BUT NOT HIGHER THAN 9,0 V./V./HR. AT WHICH, AT SAIDSELECTED TEMPERATURE, NOT MORE THAN 20% WT. OF THE FEEDSTOCK ISCONVERTED TO MATERIAL BOILING BELOW 150*C.; MAINTAINING A SELECTEDPRESSURE IN SAID ZONE IN THE RANGE 100-1500 P.S.I.G.A., SAID SELECTEDTEMPERATURE AND SAID SELECTED SPACE VELOCITY BEING CORRELATED TO REDUCETHE POUR POINT OF THE FEEDSTOCK SUCH THAT THE POUR POINT OF THE MATERIALOF THE TREATED DISTILLATE FRACTION BOILING ABOVE 150*C. IS AT LEAST 5*F.LOWER THAN THE POUR POINT OF THE FEEDSTOCK, AND RECOVERING THE TREATEDDISTILLATE FRACTION.